Subject: Re: Determining bjt noise parameters for Spice models?
Date: Sat, 14 Dec 2002 11:04:51 +0100
Organization: Wanadoo, l'internet avec France Telecom
References: <3DF6537E.B0FC9DBE@worldonline.fr> <3DF90203.C9691374@worldonline.fr> <3DF98E5B.D86102A5@worldonline.fr> <3DFA392F.7FEE50B6@worldonline.fr> <3DFA632B.BA056C3B@worldonline.fr> <3DFAFD58.FE3D4250@worldonline.fr>
NNTP-Posting-Date: 14 Dec 2002 10:04:52 GMT
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Don Pearce wrote:
> On Sat, 14 Dec 2002 10:43:52 +0100, "A.Iakovlev"
> >Well, I've then simulated my circuit (a voltage follower) and have obtained
> >huge noise figures (about 0.2 uV/sqHz @ 5kHz)! Something looks wrong with the
> >model. I have then set RB and KF for 2SA876 the same as for 2SC1775 (its
> >complementary), and the circuit noise figure became reasonable... But
> >I believe that the model could still be improved.
> If you do the calculation again, but using uV/rootHz, what do you see?
Yes, I meant sqHz = square root of Hertz. The circuit noise density (input or
output) became about 3.25 nV / Sqrt(Hz) in the 100Hz-10kHz band. I've made a
typo, it's 2SA872.
> Telecommunications consultant